1. The mechanism of the prolongation of pregnancy in the rabbit
2. Stander, Henricus J.: In Williams' Obstetrics, New York, D. Appleton-Century Co., p. 529.
3. DeLee, Joseph B.: Principles and Practice of Obstetrics, Philadelphia, W. B. Saunders Co., p. 523.
4. Davis, C. H., and McDonald, R. E.: Obstetrics and Gynecology, Chap. 17, 1: Philadelphia, W. B. Saunders Co., p. 32.